Phase detection data encoding techniques

Abstract

This disclosure provides systems, methods, and devices for image signal processing that support compression of phase detection (PD) data. In a first aspect, a method of image processing includes receiving image data and first phase detection data corresponding to the image data; determining a first channel of the first phase detection data and a second channel of the first phase detection data; and coding the first phase detection data to determine second phase detection data by separately coding the first channel and the second channel. Other aspects and features are also claimed and described.

What is claimed is: 
     
       1. A method, comprising:
 receiving image data and first phase detection data corresponding to the image data; 
 determining a first channel of the first phase detection data and a second channel of the first phase detection data; and 
 coding the first phase detection data to determine second phase detection data by separately coding the first channel and the second channel, wherein coding the first phase detection data comprises:
 determining a focus state; and 
 based on at least one criteria involving the focus state, coding the first phase detection data by:
 coding at least one of the first channel or the second channel based on same-channel correlation; or 
 coding the at least one of the first channel or the second channel based on cross-channel correlation. 
 
 
 
     
     
       2. The method of  claim 1 , wherein coding the first phase detection data comprises coding the first phase detection data based on a same-channel correlation of at least one of the first channel or the second channel. 
     
     
       3. The method of  claim 1 , wherein coding the first phase detection data comprises coding the first phase detection data based on cross-channel correlation between the first channel and the second channel. 
     
     
       4. The method of  claim 1 , wherein coding the first phase detection data comprises:
 coding the first channel based on same-channel correlation; and 
 coding the second channel based on cross-channel correlation of the second channel with the first channel. 
 
     
     
       5. The method of  claim 1 , wherein coding the first phase detection data comprises high-pass filtering lower-frequency components below a threshold frequency of the first phase detection data. 
     
     
       6. The method of  claim 5 , further comprising tuning a frequency response of the high-pass filtering by adjusting the threshold frequency based on one or more criteria. 
     
     
       7. The method of  claim 6 , wherein adjusting the threshold frequency comprises adjusting the threshold frequency based on luminosity of a scene represented by the first phase detection data. 
     
     
       8. The method of  claim 1 , wherein:
 receiving the image data and the first phase detection data comprises receiving the image data and the first phase detection data from an image sensor, and 
 coding the first phase detection data comprises encoding the first phase detection data to determine the second phase detection data; and 
 
       the method further comprises:
 transmitting the second phase detection data on a data bus to an image signal processor. 
 
     
     
       9. The method of  claim 1 , wherein:
 receiving the image data and the first phase detection data comprises receiving the image data and the first phase detection data from an image sensor through a data bus, and 
 coding the first phase detection data comprises decoding the first phase detection data to determine the second phase detection data, 
 
       the method further comprises:
 determining a focus position based on the second phase detection data; and 
 controlling a lens coupled to the image sensor based on determining the focus position. 
 
     
     
       10. An apparatus, comprising:
 a memory storing processor-readable code; and 
 at least one processor coupled to the memory, the at least one processor configured to execute the processor-readable code to cause the at least one processor to perform operations including:
 receiving image data and first phase detection data corresponding to the image data; 
 determining a first channel of the first phase detection data and a second channel of the first phase detection data; and 
 coding the first phase detection data to determine second phase detection data by separately coding the first channel and the second channel, wherein coding the first phase detection data comprises: 
 determining a focus state; and 
 based on at least one criteria involving the focus state, coding the first phase detection data by:
 coding at least one of the first channel or the second channel based on same-channel correlation; or 
 coding the at least one of the first channel or the second channel based on cross-channel correlation. 
 
 
 
     
     
       11. The apparatus of  claim 10 , wherein coding the first phase detection data comprises coding the first phase detection data based on a same-channel correlation of at least one of the first channel or the second channel. 
     
     
       12. The apparatus of  claim 10 , wherein coding the first phase detection data comprises coding the first phase detection data based on cross-channel correlation between the first channel and the second channel. 
     
     
       13. The apparatus of  claim 10 , wherein coding the first phase detection data comprises:
 coding the first channel based on same-channel correlation; and 
 coding the second channel based on cross-channel correlation of the second channel with the first channel. 
 
     
     
       14. The apparatus of  claim 10 , wherein coding the first phase detection data comprises high-pass filtering lower-frequency components below a threshold frequency of the first phase detection data. 
     
     
       15. The apparatus of  claim 14 , wherein the at least one processor is configured to perform further operations comprising tuning a frequency response of the high-pass filtering by adjusting the threshold frequency based on one or more criteria. 
     
     
       16. The apparatus of  claim 15 , wherein adjusting the threshold frequency comprises adjusting the threshold frequency based on luminosity of a scene represented by the first phase detection data. 
     
     
       17. The apparatus of  claim 10 , wherein:
 receiving the image data and the first phase detection data comprises receiving the image data and the first phase detection data from an image sensor, and 
 coding the first phase detection data comprises encoding the first phase detection data to determine the second phase detection data; and 
 
       the at least one processor configured to perform further operations comprising:
 transmitting the second phase detection data on a data bus to an image signal processor. 
 
     
     
       18. The apparatus of  claim 10 , wherein:
 receiving the image data and the first phase detection data comprises receiving the image data and the first phase detection data from an image sensor through a data bus, and 
 coding the first phase detection data comprises decoding the first phase detection data to determine the second phase detection data, 
 
       the at least one processor configured to perform further operations comprising:
 determining a focus position based on the second phase detection data; and 
 controlling a lens coupled to the image sensor based on determining the focus position. 
 
     
     
       19. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations comprising:
 receiving image data and first phase detection data corresponding to the image data; 
 determining a first channel of the first phase detection data and a second channel of the first phase detection data; and 
 coding the first phase detection data to determine second phase detection data by separately coding the first channel and the second channel, wherein coding the first phase detection data comprises:
 determining a focus state; and 
 based on at least one criteria involving the focus state, coding the first phase detection data by:
 coding at least one of the first channel or the second channel based on same-channel correlation; or 
 coding the at least one of the first channel or the second channel based on cross-channel correlation. 
 
 
 
     
     
       20. The non-transitory, computer-readable medium of  claim 19 , wherein coding the first phase detection data comprises coding the first phase detection data based on a same-channel correlation of at least one of the first channel or the second channel. 
     
     
       21. The non-transitory, computer-readable medium of  claim 19 , wherein coding the first phase detection data comprises coding the first phase detection data based on cross-channel correlation between the first channel and the second channel. 
     
     
       22. The non-transitory, computer-readable medium of  claim 19 , wherein coding the first phase detection data comprises:
 coding the first channel based on same-channel correlation; and 
 coding the second channel based on cross-channel correlation of the second channel with the first channel. 
 
     
     
       23. An image capture device, comprising: an image sensor comprising a phase detection (PD) compression module, the image sensor configured to output image data and to output corresponding first phase detection (PD) data compressed by the PD compression module; a memory storing processor-readable code; and at least one processor coupled to the memory and to the image sensor, the at least one processor configured to execute the processor-readable code to cause the at least one processor to perform operations comprising: receiving, by the at least one processor from the image sensor over a data bus, the image data and the first phase detection data; determining, by the at least one processor, a first channel of the first phase detection data and a second channel of the first phase detection data; and decompressing, by the at least one processor, the first phase detection data to determine second phase detection data by separately decoding the first channel and the second channel, wherein coding the first phase detection data comprises filtering lower-frequency components below a threshold frequency of the first phase detection data. 
     
     
       24. The image capture device of  claim 23 , wherein coding the first phase detection data comprises coding the first phase detection data based on a same-channel correlation of at least one of the first channel or the second channel. 
     
     
       25. The image capture device of  claim 23 , wherein coding the first phase detection data comprises coding the first phase detection data based on cross-channel correlation between the first channel and the second channel. 
     
     
       26. The image capture device of  claim 23 , wherein the at least one processor is configured to perform further operations comprising adjusting the threshold frequency by adjusting the threshold frequency based on luminosity of a scene represented by the first phase detection data. 
     
     
       27. A method, comprising:
 receiving image data and first phase detection data corresponding to the image data; 
 determining a first channel of the first phase detection data and a second channel of the first phase detection data; and 
 coding the first phase detection data to determine second phase detection data by separately coding the first channel and the second channel, wherein coding the first phase detection data comprises high-pass filtering lower-frequency components below a threshold frequency of the first phase detection data. 
 
     
     
       28. An apparatus, comprising:
 a memory storing processor-readable code; and 
 at least one processor coupled to the memory, the at least one processor configured to execute the processor-readable code to cause the at least one processor to perform operations including:
 receiving image data and first phase detection data corresponding to the image data; 
 determining a first channel of the first phase detection data and a second channel of the first phase detection data; and 
 coding the first phase detection data to determine second phase detection data by separately coding the first channel and the second channel, wherein coding the first phase detection data comprises high-pass filtering lower-frequency components below a threshold frequency of the first phase detection data.